Microprocessor-based biomedical instrumentation introduces features not possible with previous types of units. The instruments are able to control an experiment, do calculations on the data, and make decisions based on the results. The advantages to the researcher are that he can do experiments not possible before and measure results as they occur. We have built several such instruments, all designed for laboratory use. The oxygen equilibrium curve analyzer allows a relatively unskilled technician to generate 10 to 12 oxygen equilibrium curves a day on whole blood. The results are displayed, plotted, and stored for future use. The instrument is being used to determine the significance of shifts in oxygen affinity in human blood. The microcalorimeter heat correction unit converts a voltage into a heat of reaction in real time. The unit also does baseline correction and computes the rate of change of heat of reaction at selected times. The data is printed, displayed, and stored for future use. The temperature probe uses a microprocessor to linearize a thermistor over a range of 100 degrees C with an absolute accuracy of 0.001 degrees C.